1. Field of the Invention
The present invention relates generally to a microstrip antenna for use on a missile or the like. More specifically, the present invention relates to a microstrip antenna which receives GPS (global positioning system) data and which is adapted for use on a small diameter projectile such as a missile.
2. Description of the Prior Art
A microstrip antenna operates by resonating at a frequency. The conventional design for a microstrip antenna utilizes printed circuit board techniques to mount a printed copper patch on the top layer of a dielectric with a ground plane on the bottom of the dielectric. The frequency at which the microstrip antenna operates is approximately a half wavelength in the microstrip medium of dielectric below the copper patch and air above the copper patch.
However, there is a need to isolate the microstrip antenna from radio frequency signals at different frequencies than the operating frequency for the microstrip antenna. There is also a need to protect the antenna and to provide for signal amplification. Dimensions of the antenna are also critical in that the antenna is usually designed for use on a specific projectile.
Currently, there is need for a conformal wrap-around antenna to generate a quasi omni-directional radiation pattern. The antenna must have a 14-inch maximum diameter and a 5 inch maximum width. The required frequency of operation is 1565 Mhz to 1585 Mhz, which is the GPS frequency band and the required polarization is right hand circular polarization. A low noise amplifier with input protection is necessary and needs to be integrated into the antenna.
Accordingly, there is a need for a microstrip antenna which operates in the GPS frequency band, requires minimal space, and provides for isolation, protection and amplification.